As the available sources of fuel and energy become more scarce and as energy costs reach ever higher levels there is a growing interest in new sources of energy and also in the conservation and full utilization of the energy now produced.
Of special interest to this invention is the efficient utilization of available energy within a building for control of the temperature in the living areas of the structure. A significant amount of energy enters the building for use in lighting, for example, and a major part of the heat developed by the lighting system is radiated to the air space above the lighting fixtures. From there it passes through the roof and is lost to the outside.
In some areas of the country there is a wide temperature range between daytime and nightime temperatures, and during certain seasons of the year there is often a need for heating during the night and for cooling during the day. As a general rule, heat generated during the day by lighting fixtures and other heat generating equipment is eliminated by the air conditioning system and additional energy purchased from the public utilities is required for heating during the night. The waste and inefficiency of such a system is obvious and demanding of correction.
In the present climate of expensive energy in increasingly short supply there is, therefore, an important need for improved heating and air conditioning systems which more fully utilize the available energy.